This invention relates in general to a filter for separating particles from a flow of dirty liquid such as machine tool coolant. More particularly, the invention relates to a filter of the type in which an indexable filter web made of paper, fabric or the like is carried along a curved path through a tank of liquid by a flexible and endless perforated conveyor such as, for example, a so-called Cambridge belt. Filtering occurs as liquid from a dirty pool passes through the filter web. When the active portion of the web becomes clogged with particles, the web is indexed by the conveyor to bring a clean length of web into the filtering area.
A filter of the foregoing general type is disclosed in Gross U.S. Pat. No. 2,720,973. That filter is a gravity filter in that dirty liquid is located above the filter web and flows downwardly through the web by gravity and into a clean pool beneath the web. The web and the conveyor are supported by a pair of laterally spaced discs which form the web into a curved pocket. The conveyor presses the side margins of the web against the peripheral surfaces of the discs to seal the web to the discs and prevent liquid from flowing from the dirty pool to the clean pool without passing through the web and being filtered. When the web is indexed, the discs rotate and, as an incident thereto, the web and conveyor move with the discs.